// 递增++ 递减--

//前置，变量的值在语句被求值之前被改变

var num = 20;

var num2 = 0;

num2 = ++num + 2;
console.log(num2); //22

num2 = num + 2; //22
console.log(num2);

//后置，变量的值在语句被求值之后改变

var num3 = 50;
var num4 = 0;

num4 = num3-- + 2;
console.log(num4); //52

num4 = num3 + 2;
console.log(num4); //50

while (a > 25) {

    console.log(a);

    ++a;

}

for (let index = 0; index < array.length; index++) {
    const element = array[index];
}

a += 123;